Imaging element and method for manufacturing imaging element

ABSTRACT

A step of forming an on-chip lens of a phase difference pixel is simplified. An imaging element includes a pixel array unit, an individual on-chip lens, a common on-chip lens, and an adjacent on-chip lens. In the pixel array unit, pixels that performs photoelectric conversion according to incident light components, a plurality of phase difference pixels that is included in the pixels, is arranged adjacent to each other, and detects a phase difference, and phase difference pixel adjacent pixels that are included in the pixels and are adjacent to the phase difference pixels are arranged two-dimensionally. The individual on-chip lens is arranged for each of the pixels and individually condenses the incident light components on corresponding one of the pixels. The common on-chip lens is commonly arranged in the plurality of phase difference pixels and commonly condenses the incident light component. The adjacent on-chip lens is arranged for each of the phase difference pixel adjacent pixels, individually condenses the incident light components on corresponding one of the phase difference pixel adjacent pixels, and is formed to have a size different from the individual on-chip lens to adjust a shape of the common on-chip lens.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of U.S. Pat.Application Serial No. 17/943,052, filed Sep. 12, 2022, which is acontinuation application of U.S. Pat. Application No. 17/250,307, filedon Dec. 31, 2020, now U.S. Patent No. 11,477,403, which is a U.S.National Phase of International Pat. Application No. PCT/JP2019/023301filed on Jun. 12, 2019, which claims priority benefit of Japanese Pat.Application No. JP 2018-129652 filed in the Japan Patent Office on Jul.09, 2018. Each of the above-referenced applications is herebyincorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to an imaging element and a method formanufacturing the imaging element. More specifically, the presentdisclosure relates to an imaging element that detects an image planephase difference and a method for manufacturing the imaging element.

BACKGROUND ART

Conventionally, an imaging element that performs autofocus has beenused. For example, an imaging element is used that performs autofocus byarranging phase difference pixels that detect an image plane phasedifference to detect a focal position of a subject, and adjusting aposition of an imaging lens according to the detected focal position. Atthis time, the phase difference pixels include a pair of pixels. Lightcomponents transmitted through different positions of the imaging lens,for example, a right side and a left side of the imaging lens, are eachincident on the pair of phase difference pixels to perform imaging, andan image signal is generated for each phase difference pixel. A phasedifference of an image based on each of the generated image signals isdetected, so that the focal position can be detected. A method ofdividing the light component transmitted through the imaging lens intotwo in this way is called pupil division.

As such an imaging element, an imaging element is used in which anon-chip lens common to two adjacent pixels is arranged to form phasedifference pixels, so that the pupil division is performed. Bycondensing light components from a subject on the two pixels through thecommonly arranged on-chip lens, it is possible to apply, to thesepixels, light components transmitted through different positions of animaging lens. For example, an imaging element has been proposed in whicha first microlens and a film covering the first microlens are formed foreach pixel, and a second microlens is formed on a surface of a film of afocus detection pixel (see, for example, Patent Document 1). In thisconventional technology, the microlenses and the focus detection pixelcorrespond to the on-chip lens and the phase difference pixel,respectively. Furthermore, the film on a surface of the first microlensis used as an etching stopper when the second microlens is formed byetching.

CITATION LIST Patent Document

Patent Document 1: Japanese Patent Application Laid-Open No. 2016-001682

SUMMARY OF THE INVENTION Problems to Be Solved by the Invention

In the above-described conventional technology, a condensing point isadjusted in order to improve autofocus performance of the focusdetection pixel. To perform the adjustment of the condensing point, theon-chip lens and the film are formed on the phase difference pixel, andthen a second on-chip lens that commonly covers on-chip lenses of twophase difference pixels is formed. As described above, in theabove-described conventional technology, there is a problem that sincethe on-chip lenses of the phase difference pixels are formed by twosteps of forming the on-chip lens, the steps of forming the on-chip lensare complicated.

The present disclosure has been made in view of the above-describedproblem, and an object of the present disclosure is to simplify a stepof forming an on-chip lens of a phase difference pixel.

Solutions to Problems

The present disclosure has been made to solve the above-describedproblem, and a first aspect thereof is an imaging element including apixel array unit in which pixels that perform photoelectric conversionaccording to incident light components, a plurality of phase differencepixels that is included in the pixels, is arranged adjacent to eachother, and detects a phase difference, and phase difference pixeladjacent pixels that are included in the pixels and are adjacent to thephase difference pixels are arranged two-dimensionally, an individualon-chip lens that is arranged for each of the pixels and individuallycondenses the incident light components on corresponding one of thepixels, a common on-chip lens that is commonly arranged in the pluralityof phase difference pixels and commonly condenses the incident lightcomponents, and an adjacent on-chip lens that is arranged for each ofthe phase difference pixel adjacent pixels, individually condenses theincident light components on corresponding one of the phase differencepixel adjacent pixels, and is formed to have a size different from theindividual on-chip lens to adjust a shape of the common on-chip lens.

Furthermore, in this first aspect, the adjacent on-chip lens may beformed to have a size larger than the individual on-chip lens.

Furthermore, in this first aspect, the adjacent on-chip lens may beformed to have a bottom portion with a width larger than the individualon-chip lens.

Furthermore, in this first aspect, an adjacent on-chip lens adjacent tothe common on-chip lens at an apex may be formed to have a size largerthan an adjacent on-chip lens adjacent to the common on-chip lens on aside.

Furthermore, in the first aspect, the individual on-chip lens may bearranged so that a position relative to corresponding one of the pixelsis shifted according to an incident angle of the incident lightcomponents, the adjacent on-chip lens may be arranged so that a positionrelative to corresponding one of the phase difference pixel adjacentpixels is shifted according to the incident angle of the incident lightcomponents, and the common on-chip lens may be arranged so that aposition relative to the phase difference pixels is shifted according tothe incident angle of the incident light components.

Furthermore, in the first aspect, among peripheral adjacent on-chiplenses that are adjacent on-chip lenses adjacent to a peripheral commonon-chip lens which is a common on-chip lens arranged in a periphery ofthe pixel array unit, a peripheral adjacent on-chip lens close to anoptical center of the pixel array unit and a peripheral adjacent on-chiplens close to an end portion of the pixel array unit may be formed tohave different sizes.

Furthermore, in the first aspect, among the peripheral adjacent on-chiplenses, the peripheral adjacent on-chip lens close to the optical centerof the pixel array unit may be formed to have a size smaller than theperipheral adjacent on-chip lens close to the end portion of the pixelarray unit, which is arranged symmetrically with respect to theperipheral common on-chip lens.

Furthermore, in the first aspect, a peripheral close-adjacent on-chiplens that is a peripheral adjacent on-chip lens arranged between theperipheral common on-chip lens and the optical center of the pixel arrayunit may be formed to have a size smaller than a peripheral far-adjacenton-chip lens that is a peripheral adjacent on-chip lens arrangedsymmetrically with respect to the peripheral common on-chip lens.

Furthermore, in this first aspect, the peripheral close-adjacent on-chiplens may be formed to have a size smaller than an individual on-chiplens adjacent to the peripheral close-adjacent on-chip lens.

Furthermore, in this first aspect, the peripheral far-adjacent on-chiplens may be formed to have a size larger than an individual on-chip lensadjacent to the peripheral far-adjacent on-chip lens.

Furthermore, in this first aspect, the adjacent on-chip lens may beformed at different heights between a bottom portion of a regionadjacent to the common on-chip lens and a bottom portion of a regionadjacent to the individual on-chip lens.

Furthermore, in the first aspect, a shape of a bottom surface of theadjacent on-chip lens may be formed as a shape different from a bottomsurface of the phase difference pixel adjacent pixels.

Furthermore, in this first aspect, the common on-chip lens may commonlycondense the incident light components on two of the phase differencepixels.

Furthermore, in this first aspect, the common on-chip lens may commonlycondense the incident light components on four of the phase differencepixels.

Furthermore, in this first aspect, the plurality of phase differencepixels may perform pupil division on the incident light components todetect the phase difference.

Furthermore, a second aspect of the present disclosure is a method formanufacturing an imaging element, the method including a step of forminga pixel array unit in which pixels that perform photoelectric conversionaccording to incident light components, a plurality of phase differencepixels that is included in the pixels, is arranged adjacent to eachother, and detects a phase difference, and phase difference pixeladjacent pixels that are included in the pixels and are adjacent to thephase difference pixels are arranged two-dimensionally, a step offorming an individual on-chip lens that is arranged for each of thepixels and individually condenses the incident light components oncorresponding one of the pixels, a step of forming a common on-chip lensthat is commonly arranged in the plurality of phase difference pixelsand commonly condenses the incident light components, and a step offorming an adjacent on-chip lens that is arranged for each of the phasedifference pixel adjacent pixels, individually condenses the incidentlight components on corresponding one of the phase difference pixeladjacent pixels, and is formed to have a size different from theindividual on-chip lens to adjust a shape of the common on-chip lens.

In the above-described aspects, the adjacent on-chip lens is formed tohave a size different from the individual on-chip lens, so that aneffect of adjusting the shape of the common on-chip lens is obtained. Itis assumed that the individual on-chip lens, the adjacent on-chip lens,and the common on-chip lens are manufactured by a common step.

Effects of the Invention

According to the present disclosure, it is possible to obtain anexcellent effect of simplifying a step of forming an on-chip lens of aphase difference pixel.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a configuration example of an imagingelement according to embodiments of the present disclosure.

FIG. 2 is a diagram illustrating a configuration example of on-chiplenses according to a first embodiment of the present disclosure.

FIG. 3 is a cross-sectional view illustrating a configuration example ofthe imaging element according to the first embodiment of the presentdisclosure.

FIG. 4 is a diagram illustrating a configuration example of colorfilters according to the embodiments of the present disclosure.

FIGS. 5A, 5B, and 5C are diagrams illustrating a configuration exampleof the color filters according to the embodiments of the presentdisclosure.

FIGS. 6A, 6B, and 6C are diagrams illustrating another configurationexample of the color filters according to the embodiments of the presentdisclosure.

FIGS. 7A, 7B, and 7C are diagrams illustrating an example of a methodfor manufacturing the imaging element according to the first embodimentof the present disclosure.

FIGS. 8A, 8B, and 8C are diagrams illustrating an example of the methodfor manufacturing the imaging element according to the first embodimentof the present disclosure.

FIG. 9 is a diagram illustrating an example of a method formanufacturing the on-chip lenses according to the first embodiment ofthe present disclosure.

FIGS. 10A and 10B are cross-sectional views illustrating a configurationexample of an imaging element according to a modified example of thefirst embodiment of the present disclosure.

FIG. 11 is a cross-sectional view illustrating another configurationexample of the imaging element according to the modified example of thefirst embodiment of the present disclosure.

FIG. 12 is a diagram illustrating a configuration example of on-chiplenses according to a second embodiment of the present disclosure.

FIG. 13 is a cross-sectional view illustrating a configuration exampleof an imaging element according to the second embodiment of the presentdisclosure.

FIG. 14 is a diagram illustrating a configuration example of the on-chiplenses according to the second embodiment of the present disclosure.

FIG. 15 is a cross-sectional view illustrating a configuration exampleof the imaging element according to the second embodiment of the presentdisclosure.

FIG. 16 is a diagram illustrating a configuration example of the on-chiplenses according to the second embodiment of the present disclosure.

FIG. 17 is a diagram illustrating a configuration example of on-chiplenses according to a third embodiment of the present disclosure.

FIGS. 18A, 18B, and 18C are cross-sectional views illustrating aconfiguration example of an imaging element according to the thirdembodiment of the present disclosure.

FIG. 19 is a block diagram illustrating a schematic configurationexample of a camera that is an example of an imaging device to which thepresent disclosure can be applied.

MODE FOR CARRYING OUT THE INVENTION

Next, modes for carrying out the present disclosure (hereinafter,referred to as embodiments) will be described with reference to thedrawings. In the following drawings, the same or similar reference signsare given to the same or similar parts. However, the drawings areschematic, and a dimensional ratio of each part and the like do notalways match an actual ones. Furthermore, it is needless to say thatportions having different dimensional relationships and ratios betweenthe drawings are also included. In addition, the embodiments will bedescribed in the following order.

-   1. First Embodiment-   2. Second Embodiment-   3. Third Embodiment-   4. Application Example to Camera

1. First Embodiment [Configuration of Imaging Element]

FIG. 1 is a cross-sectional view illustrating a configuration example ofan imaging element according to the embodiments of the presentdisclosure. An imaging element 1 in FIG. 1 includes a pixel array unit10, a vertical drive unit 20, a column signal processing unit 30, and acontrol unit 40.

The pixel array unit 10 is formed by arranging pixels 100 in atwo-dimensional lattice shape. Here, each of the pixels 100 generates animage signal according to an applied light component. The pixel 100includes a photoelectric conversion unit that generates an electriccharge according to the applied light component. The pixel 100 furtherincludes a pixel circuit. This pixel circuit generates an image signalbased on the electric charge generated by the photoelectric conversionunit. The generation of the image signal is controlled by a controlsignal generated by the vertical drive unit 20 described later. In thepixel array unit 10, signal lines 11 and 12 are arranged in an X-Ymatrix. The signal line 11 is a signal line that transmits the controlsignal for the pixel circuit of the pixel 100, is arranged for each rowof the pixel array unit 10, and is commonly wired to the pixels 100arranged in each row. The signal line 12 is a signal line that transmitsthe image signal generated by the pixel circuit of the pixel 100, isarranged for each column of the pixel array unit 10, and is commonlywired to the pixels 100 arranged in each column. These photoelectricconversion units and pixel circuits are formed on a semiconductorsubstrate.

The vertical drive unit 20 generates the control signal for the pixelcircuit of the pixel 100. The vertical drive unit 20 transmits thegenerated control signal to the pixel 100 via the signal line 11 in FIG.1 . The column signal processing unit 30 processes the image signalgenerated by the pixel 100. The column signal processing unit 30processes the image signal transmitted from the pixel 100 via the signalline 12 in FIG. 1 . The processing in the column signal processing unit30 corresponds to, for example, analog-digital conversion that convertsan analog image signal generated in the pixel 100 into a digital imagesignal. The image signal processed by the column signal processing unit30 is output as an image signal of the imaging element 1. The controlunit 40 controls the entire imaging element 1. The control unit 40controls the imaging element 1 by generating and outputting controlsignals that control the vertical drive unit 20 and the column signalprocessing unit 30. The control signals generated by the control unit 40are transmitted to the vertical drive unit 20 and the column signalprocessing unit 30 via signal lines 41 and 42, respectively.

In addition to the pixels 100, phase difference pixels 300 and phasedifference pixel adjacent pixels 200 are further arranged in the pixelarray unit 10 described above. In FIG. 1 , pixels hatched with crossingoblique lines and pixels hatched with parallel oblique lines correspondto the phase difference pixels 300 and the phase difference pixeladjacent pixels 200, respectively. The phase difference pixels 300 arepixels for detecting an image plane phase difference. The phasedifference pixels 300 are arranged adjacent to each other on the leftand right, for example, to perform pupil division. A plurality of suchphase difference pixels 300 adjacent to each other on the left and rightis linearly arranged in the pixel array unit 10. Image signals generatedby the plurality of phase difference pixels 300 are output from theimaging element 1 and processed by a device such as a camera that usesthe imaging element 1. Specifically, the image signals generated by thephase difference pixels 300 adjacent to each other on the left and rightgenerate images by light components transmitted through a right side anda left side of an imaging lens. When a phase difference in these imagesis detected, a focal position of a subject is detected, and a positionof the imaging lens is adjusted on the basis of the detected focalposition, so that autofocus is executed.

Furthermore, the phase difference pixel adjacent pixels 200 are pixelsarranged adjacent to the two phase difference pixels 300 so as tosurround a periphery of the two phase difference pixels 300. In thephase difference pixels 300 and the phase difference pixel adjacentpixels 200, photoelectric conversion units and pixel circuits having thesame configurations as those in the pixels 100 are arranged. That is,the phase difference pixels 300 and the phase difference pixel adjacentpixels 200 can have the same configuration as the pixels 100 in adiffusion region or the like of the semiconductor substrate. As will bedescribed later, on-chip lenses having different shapes are arranged inthe pixels 100, the phase difference pixels 300, and the phasedifference pixel adjacent pixels 200. Here, the on-chip lenses arelenses that condense light components from the subject on thephotoelectric conversion units of the pixels 100 and the like.

[Configuration of On-Chip Lens]

FIG. 2 is a diagram illustrating a configuration example of the on-chiplenses according to the first embodiment of the present disclosure. FIG.2 is a diagram illustrating a configuration example of the pixel arrayunit 10, and is a diagram illustrating the configuration example of theon-chip lenses in the pixels 100, the phase difference pixel adjacentpixels 200, and the phase difference pixels 300. As described withreference to FIG. 1 , the pixel array unit 10 is formed such that thephase difference pixel adjacent pixels 200 and the phase differencepixels 300 are arranged among the plurality of pixels 100. In FIG. 2 ,solid squares represent on-chip lenses 110 of the pixels 100. A solidhexagon hatched with crossing oblique lines represents an on-chip lens310 that is commonly arranged in the two phase difference pixels 300(hereinafter referred to as a common on-chip lens). Solid quadrangleshatched with parallel oblique lines other than the on-chip lenses 110and the common on-chip lens 310 represent on-chip lenses of the phasedifference pixel adjacent pixels 200. The on-chip lenses of the phasedifference pixel adjacent pixels 200 are referred to as adjacent on-chiplenses. In FIG. 2 , adjacent on-chip lenses 210 to 219 are arrangedaround the common on-chip lens 310. Note that each of the on-chip lenses110 is an example of an individual on-chip lens described in the claims.

The on-chip lenses 110 are formed to have substantially the same shapeas the pixels 100 in a plan view, and each have a rectangular bottomsurface. A curved surface is formed convexly from this bottom surface toform a lens shape, so that incident light components are condensed.Furthermore, the phase difference pixels 300 and the phase differencepixel adjacent pixels 200 are formed to have substantially the sameshape as the pixels 100. Dotted lines in FIG. 2 represent the phasedifference pixel adjacent pixels 200 and the phase difference pixels300. As illustrated in FIG. 2 , the common on-chip lens 310 is formed tohave a shape with an area smaller than a total area of the two phasedifference pixels 300. Furthermore, the common on-chip lens 310 isformed as a hexagon in which long sides of a rectangular shape formedwith the two phase difference pixels 300 are divided into two parts andtaper toward short sides of the rectangular shape, and is formed to havea bottom surface that approximates an ellipse. In addition, the commonon-chip lens 310 is formed to have a shape in which a size in the longside direction described above is reduced. By forming the common on-chiplens 310 to have such a shape, it is possible to improve the separationaccuracy of pupil division in the phase difference pixels 300 andimprove the detection accuracy of the phase difference. Details of theshape of the common on-chip lens 310 will be described later.

The adjacent on-chip lenses 210 to 219 arranged around the commonon-chip lens 310 are formed to have shapes and sizes different from theon-chip lenses 110. Specifically, the adjacent on-chip lenses 210 to 219are formed to have shapes in which regions adjacent to the phasedifference pixels 300 overhang the phase difference pixels 300, andformed to have sizes larger than the on-chip lenses 110. Furthermore,among the adjacent on-chip lenses 210 to 219, the adjacent on-chiplenses 211, 214, 216, and 219 adjacent to the common on-chip lens 310 atapexes are formed to have sizes larger than the adjacent on-chip lenses210, 212, 213, 215, 217, and 218 adjacent to the common on-chip lens 310on sides. As a result, the adjacent on-chip lenses 210 to 219 are formedto have shapes in which regions adjacent to the vicinity of theabove-described short sides of the common on-chip lens 310 overhang thephase difference pixels 300. The shape of the common on-chip lens 310 isadjusted by the overhang of the adjacent on-chip lenses. By forming theadjacent on-chip lenses 210 to 219 to have sizes larger than the on-chiplenses 110, it is possible to adjust the shape of the common on-chiplens 310.

[Configuration of Imaging Element]

FIG. 3 is a cross-sectional view illustrating a configuration example ofthe imaging element according to the first embodiment of the presentdisclosure. FIG. 3 is a cross-sectional view illustrating aconfiguration of a cross section of the imaging element 1 (pixel arrayunit 10) along a line A-A′ in FIG. 2 . The imaging element 1 in FIG. 3includes a semiconductor substrate 150, a wiring region 160, colorfilters 141, light-shielding films 142, a flattening film 130, theon-chip lenses 110, and a support substrate 170. Note that, in the phasedifference pixels 300, the common on-chip lens 310 is arranged insteadof the on-chip lenses 110. In the phase difference pixel adjacent pixels200, the adjacent on-chip lenses 210 and 215 are arranged instead of theon-chip lenses 110.

The semiconductor substrate 150 is a semiconductor substrate on whichsemiconductor element portions of the photoelectric conversion units andthe pixel circuits of the pixels 100 and the like are formed.Furthermore, semiconductor elements of the vertical drive unit 20 andthe like described with reference to FIG. 1 are further formed on thesemiconductor substrate 150. In FIG. 3 , the photoelectric conversionunits among these semiconductor elements are illustrated. Elements suchas the photoelectric conversion units are formed in a well region 151formed in the semiconductor substrate 150. For convenience, it isassumed that the semiconductor substrate 150 in FIG. 3 forms a p-typewell region 151. An n-type semiconductor region 152 is formed for eachpixel in the p-type well region 151. A photodiode is formed by a p-njunction formed at an interface between the n-type semiconductor region152 and the p-type well region 151 around the n-type semiconductorregion 152. This photodiode corresponds to the photoelectric conversionunit. In the semiconductor substrate 150, separation portions 153 arearranged at the boundary of the pixels 100 and the like. Each of theseparation portions 153 includes an insulating film or the like, andelectrically separates the pixels 100 and the like.

The wiring region 160 is a region where wiring of the pixel circuits andthe like is formed. This wiring region includes a wiring layer 162 andan insulating layer 161. The wiring layer 162 is a wiring that includesmetal or the like and transmits a signal such as an image signal. Theinsulating layer 161 insulates the wiring layer 162. The wiring layer162 and the insulating layer 161 can be formed in multiple layers.

The support substrate 170 is a substrate that supports the imagingelement 1. Arranging the support substrate 170 can improve the strengthof the imaging element 1 in a manufacturing step of the imaging element1.

Each of the color filters 141 is an optical filter through which a lightcomponent having a predetermined wavelength among the incident lightcomponents is transmitted. As the color filters 141, color filters 141through which a red light component, a green light component, and a bluelight component are transmitted can be used. The light-shielding films142 are arranged at the boundary of the color filters 141 adjacent toeach other to block the incident light components obliquely transmittedthrough the color filters 141. Arranging the light-shielding films 142can prevent color mixing. Each of the light-shielding films 142 caninclude a material having a light-shielding property, for example, metalsuch as aluminum or tungsten.

The flattening film 130 is a film that flattens surfaces of the pixels100 and the like. This flattening film 130 can include a resin or thelike, and can include the same material as the on-chip lenses 110 andthe like described later.

The on-chip lenses 110, the adjacent on-chip lenses 210 and 215, and thecommon on-chip lens 310 are lenses that condense the incident lightcomponents on the pixels 100 and the like as described above. Theon-chip lenses 110 condense the incident light components on thevicinity of surfaces of the n-type semiconductor regions 152 of thepixels 100. Similarly, the adjacent on-chip lenses 210 and 215 condensethe incident light components on the vicinity of surfaces of the n-typesemiconductor regions 152 of the phase difference pixel adjacent pixels200. The on-chip lenses 110, the adjacent on-chip lenses 210 and 215,and the common on-chip lens 310 can include, for example, an organicmaterial such as a styrene resin, an acrylic resin, a styrene-acryliccopolymer resin, or a siloxane resin. Furthermore, inorganic materialsuch as silicon nitride or silicon oxynitride can also be included. Notethat the imaging element 1 in FIG. 3 corresponds to a back-illuminatedimaging element in which the incident light components are applied to aback surface, which is a surface different from a front surface on whichthe wiring region 160 is arranged in the semiconductor substrate 150.

The common on-chip lens 310 is arranged so as to straddle the two phasedifference pixels 300. Therefore, a light component transmitted mainlythrough the right side of the imaging lens is incident on an n-typesemiconductor region 152 a of a phase difference pixel 300 on a leftside of FIG. 3 . A light component transmitted mainly through the leftside of the imaging lens is incident on an n-type semiconductor region152 b of a phase difference pixel 300 on a right side of FIG. 3 . As aresult, it is possible to execute the pupil division in a left-rightdirection. By detecting the phase difference in the images with theimage signals of these two phase difference pixels 300, it is possibleto measure a defocus amount and detect the focal position of the imaginglens.

In order to accurately detect the focal position, it is necessary toimprove the separation accuracy of the pupil-divided phase differencepixels 300. For this purpose, it is necessary to arrange a condensingposition of the common on-chip lens 310 at the center of the two phasedifference pixels 300 and reduce a region where the light components arecondensed to a circular region. Therefore, the common on-chip lens 310is formed to have a size smaller than a region where the two phasedifference pixels 300 are combined, and a curvature of the commonon-chip lens 310 is increased to form a hemispherical shape. Asillustrated in FIG. 3 , an end portion 301 of the common on-chip lens310 is formed at a position deeper than an end portion 101 of theon-chip lens 110, so that the curvature of the common on-chip lens 310can be increased. By adjusting the shape of the common on-chip lens 310in this way, it is possible to form a point-shaped condensing region,and improve the separation accuracy of the pupil division.

The adjacent on-chip lenses 210 and 215 in FIG. 3 are formed so that endportions adjacent to the common on-chip lens 310 overhang in a directionof the common on-chip lens 310, and are formed to have bottom surfaceswith widths larger than the on-chip lenses 110. Furthermore, theadjacent on-chip lenses 210 and 215 are formed to have the same depth asthe end portion 301 of the common on-chip lens 310. As a result, theshape of the common on-chip lens 310 can be adjusted as described above.

FIG. 4 is a cross-sectional view illustrating a configuration example ofthe imaging element according to the first embodiment of the presentdisclosure. FIG. 4 is a cross-sectional view illustrating aconfiguration of a cross section of the imaging element 1 along a lineB-B′ in FIG. 2 , and is a cross-sectional view illustrating aconfiguration of the vicinity of the boundary between the two phasedifference pixels 300. Since the cross section of the imaging element 1along the line B-B′ corresponds to a cross section of a region where twoon-chip lenses 110 are in contact with each other, the on-chip lenses110 have thinner thicknesses than in FIG. 3 . On the other hand, thecommon on-chip lens 310 is formed to have the same thickness as thecommon on-chip lens 310 of FIG. 3 . The adjacent on-chip lenses 213 and217 are formed to have substantially the same width as the phasedifference pixel adjacent pixels 200, and are formed to have shapes incontact with the common on-chip lens 310.

[Configuration of Color Filter]

FIGS. 5A, 5B, and 5C are diagrams illustrating a configuration exampleof the color filters according to the embodiments of the presentdisclosure. FIGS. 5A, 5B, and 5C are diagrams illustrating an example ofarrangement of the color filters 141 in the pixel array unit 10described with reference to FIG. 2 . In FIGS. 5A, 5B, and 5C, thedescription of reference signs of parts that are the same as those ofFIG. 2 is omitted. Characters described in FIGS. 5A, 5B, and 5Crepresent types of the color filters 141 that are arranged. “R”, “G”,and “B” in FIGS. 5A, 5B, and 5C represent the color filters 141corresponding to the red light component, the green light component, andthe blue light component, respectively. Furthermore, in FIGS. 5A, 5B,and 5C, four pixels 100 of two rows and two columns in which the sametypes of color filters 141 are arranged are arranged in a Bayer array.Here, the Bayer array is an array in which the color filters 141corresponding to the green light component are arranged in a checkeredshape, and the color filters 141 corresponding to the red lightcomponent and the blue light component are arranged between the colorfilters corresponding to the green light component.

FIG. 5A illustrates an example where the phase difference pixels 300 arearranged at positions of pixels in which the color filters 141corresponding to green are arranged according to the Bayer array. Thephase difference pixels 300 can be arranged without disturbing the arrayof the color filters 141 in the pixel array unit 10.

FIG. 5B illustrates an example where the color filters 141 correspondingto the green light component are arranged in the phase difference pixels300. The pixel array unit 10 can be formed so that priority is given tothe arrangement of the phase difference pixels 300.

FIG. 5C illustrates an example where the arrangement of the colorfilters 141 in the phase difference pixels 300 is omitted. In this case,for example, the thickened flattening film 130 can be arranged in aregion of the phase difference pixels 300 where the color filters 141are arranged.

FIGS. 6A, 6B, and 6C are diagrams illustrating another configurationexample of the color filters according to the embodiment of the presentdisclosure. FIGS. 6A, 6B, and 6C illustrate an example where the pixels100 of two rows and two columns arranged in the Bayer array arearranged. FIG. 6A represents an example where different color filters141 are arranged in the two phase difference pixels 300. FIG. 6Billustrates an example where the color filters 141 corresponding to thegreen light component are arranged in the phase difference pixels 300.FIG. 6C illustrates an example where the arrangement of the colorfilters 141 in the phase difference pixels 300 is omitted.

[Method for Manufacturing Imaging Element]

FIGS. 7A, 7B, 7C, 8A, 8B, and 8C are diagrams illustrating an example ofa method for manufacturing the imaging element according to the firstembodiment of the present disclosure. FIGS. 7A, 7B, 7C, 8A, 8B, and 8Care diagrams illustrating an example of the manufacturing step of theimaging element 1. First, the p-type well region 151 and the n-typesemiconductor regions 152 are formed in the semiconductor substrate 150.Next, the wiring region 160 is formed on the semiconductor substrate150, and the support substrate 170 is bonded to the wiring region 160.Next, the back surface of the semiconductor substrate 150 is ground tobe made thinner. Next, p-type separation regions are formed between thepixels 100. This formation can be performed by ion implantation. Next,trenches are formed in the separation regions, and the separationportions 153 are arranged in these trenches. Next, the light-shieldingfilms 142 and the color filters 141 are arranged on the back surface ofthe semiconductor substrate 150 (FIG. 7A). As a result, the pixel arrayunit 10 can be formed. Note that the step is an example of a step offorming a pixel array unit described in the claims.

Next, an on-chip lens material 401 that is a material of the on-chiplenses 110 and the like is arranged on surfaces of the color filters 141(FIG. 7B). Next, a resist 402 is arranged on a surface of the on-chiplens material 401 (FIG. 7C). Next, the resist 402 is patterned to formresists 403 and 404. This patterning can be performed by the resist 402being exposed and developed in shapes of quadrangular prisms. At thistime, the resists 403 each having a bottom surface smaller than thepixels 100 are arranged in regions where the on-chip lenses 110 and theadjacent on-chip lenses 210 to 219 are formed. On the other hand, in aregion where the common on-chip lens 310 is formed, the resist 404formed to be horizontally longer than the resist 403 is arranged (FIG.8A).

Next, the imaging element 1 is heated to a temperature equal to orhigher than a softening point of the resists 403 and 404. This heatingcan be performed by a reflow furnace. As a result, the resists 403 and404 are softened to form curved surfaces, and end portions of adjacentresists 403 adhere to each other to form a resist 405 (FIG. 8B). Next,the resist 405 and the on-chip lens material 401 are etched. Thisetching can be performed by dry etching (FIG. 8C). As a result, a shapeof the resist 405 can be transferred to the on-chip lens material 401,and the on-chip lenses 110, the adjacent on-chip lenses 210 to 219, andthe common on-chip lens 310 can be formed at the same time.

Note that the step of forming the common on-chip lens 310 is an exampleof a step of forming a common on-chip lens described in the claims. Thestep of forming the adjacent on-chip lenses 210 to 219 is an example ofa step of forming an adjacent on-chip lens described in the claims. Thestep of forming the on-chip lenses 110 is an example of a step offorming an individual on-chip lens described in the claims.

[Method for Manufacturing On-Chip Lens]

FIG. 9 is a diagram illustrating an example of a method formanufacturing the on-chip lenses according to the first embodiment ofthe present disclosure. FIG. 9 is a diagram illustrating configurationexamples of the resists 403 and 404 described with reference to FIG. 8A.As illustrated in FIG. 9 , gaps 406 are formed between the adjacentresists 403. The resist 404 is formed to have short sides with the samewidth as the resist 403 and long sides that are relatively short. As aresult, gaps 407 wider than the gaps 406 are formed between the resist404 and the resists 403 adjacent to the resist 404 on the short sides.That is, the relatively wide gap 407 is formed between the resists 403arranged at positions corresponding to the adjacent on-chip lenses 210to 219 and the resist 404 corresponding to the common on-chip lens 310.

Next, when the resists 403 and 404 are softened by reflow heating,corners of the resist 403 and the like are eluted in regions of the gaps406 to form the curved surfaces of the on-chip lenses 110. As a result,the resist 405 of FIG. 8B can be generated. A part of the softenedresists 403 and 404 also flows into the gaps 407. However, since the gap407 is wider than the gap 406, a shape of a resist adjacent to the gap407 after inflow is different from that of the resist 403 adjacent tothe gap 406. Arrows in FIG. 9 illustrate a state of the inflow of theresists 403 and 404 in the gap 407. The resists 403 corresponding to theadjacent on-chip lenses 210 to 219 flow into positions overhanging indirections of the phase difference pixels 300. On the other hand, ashape of the resist 404 in the vicinity of the short sides is adjustedby the inflow of the adjacent resists 403. As a result, the resist 405described with reference to FIG. 8B can be formed.

[Modified Example]

In the imaging element 1 described above, the light-shielding film 142is omitted and the separation portion 153 is arranged between the phasedifference pixels 300, but another configuration may be used.

FIGS. 10A and 10B are cross-sectional views illustrating a configurationexample of an imaging element according to a modified example of thefirst embodiment of the present disclosure. FIG. 10A illustrates anexample where the light-shielding film 142 is arranged between the phasedifference pixels 300. Furthermore, FIG. 10B illustrates an examplewhere the separation portion 153 between the phase difference pixels 300is omitted and only a separation region 154 is arranged. Note that thelight-shielding film 142 may be arranged in the imaging element 1 inFIG. 10B.

FIG. 11 is a cross-sectional view illustrating another configurationexample of the imaging element according to the modified example of thefirst embodiment of the present disclosure. FIG. 11 illustrates anexample where a gap 155 is formed in the separation portion 152 arrangedin the phase difference pixels 300. In the phase difference pixels 300described with reference to FIG. 4 , the separation portion 152 isarranged to separate the two phase difference pixels 300. However, theincident light components of the phase difference pixels 300 may bescattered by the separation portion 152, and the accuracy of the pupildivision may decrease. In such a case, the scattering of the incidentlight components can be reduced by formation of the gap 155.

Note that the configuration of the imaging element 1 of the firstembodiment of the present disclosure is not limited to this example. Forexample, the common on-chip lens 310 described with reference to FIG. 2is commonly arranged in the two phase difference pixels 300, but acommon on-chip lens commonly arranged in four phase difference pixels300 may also be used. Furthermore, the imaging element 1 may be afront-illuminated imaging element in which the incident light componentsare applied from a side of the wiring region 160 of the semiconductorsubstrate 150.

As described above, in the imaging element 1 of the first embodiment ofthe present disclosure, the adjacent on-chip lenses 210 to 219 areformed to have sizes different from the on-chip lenses 110, so that theshape of the common on-chip lens 310 is adjusted. As a result, themanufacturing step of the common on-chip lens 310 and the like can besimplified while the separation accuracy in the pupil division of thephase difference pixels 300 is improved.

2. Second Embodiment

In the imaging element 1 of the above-described first embodiment, theon-chip lenses 110 and the like of the pixel array unit 10 are arrangedat the same position relative to the pixels 100 and the like. On theother hand, an imaging element 1 of a second embodiment of the presentdisclosure is different from the above-described first embodiment inthat on-chip lenses 110 and the like are shifted and arranged accordingto an incident angle of incident light components on pixels 100 and thelike.

As described above, the imaging element 1 is arranged in a camera or thelike, and light components from a subject are applied through an imaginglens. A camera lens including this imaging lens is arranged at aposition where an optical axis of the camera lens coincides with anoptical center of a pixel array unit 10. Here, the optical center is acenter of a region of the imaging element 1 (pixel array unit 10) towhich the light components from the subject are applied. However, sincethe pixel array unit 10 of the imaging element 1 is formed to be flat,the light components from the subject are obliquely incident on an endportion of the pixel array unit 10. Therefore, condensing positions ofthe on-chip lenses 110 and the like are deviated. Therefore, in thepixels 100 and the like arranged in a periphery of the pixel array unit10, the on-chip lenses 110 and the like are arranged so as to be shiftedfrom centers of the pixels 100 according to the incident angle of theincident light components, so that the deviation of the condensingpositions is corrected. Such correction in which the on-chip lenses aredeviated according to the incident angle of the incident lightcomponents is called pupil correction.

[Configuration of On-Chip Lens in Vicinity of Left End of Pixel ArrayUnit]

FIG. 12 is a diagram illustrating a configuration example of the on-chiplenses according to the second embodiment of the present disclosure.FIG. 12 illustrates a configuration example of on-chip lenses 110 andthe like of pixels 100 and the like arranged in the vicinity of a leftend side, among the pixels 100 and the like arranged on a periphery ofthe pixel array unit 10 described with reference to FIG. 1 . The pixelarray unit 10 in FIG. 12 is different from the pixel array unit 10described with reference to FIG. 2 in the following points. The pixels100 in FIG. 12 include on-chip lenses 112 instead of the on-chip lenses110. Phase difference pixel adjacent pixels 200 in FIG. 12 includeadjacent on-chip lenses 220 to 229 instead of the adjacent on-chiplenses 210 to 219. Phase difference pixels 300 in FIG. 12 include acommon on-chip lens 320 instead of the common on-chip lens 310.

The on-chip lenses 112, the adjacent on-chip lenses 220 to 229, and thecommon on-chip lens 320 in FIG. 12 are arranged so that the on-chiplenses 110 and the like are shifted from the centers of the pixels 100and the like according to the incident angle of the incident lightcomponents. Specifically, the on-chip lenses 112, the adjacent on-chiplenses 220 to 229, and the common on-chip lens 320 are arranged so as tobe shifted to a right direction, which is a direction of the opticalcenter of the pixel array unit 10. Furthermore, among the adjacenton-chip lenses 220 to 229, the adjacent on-chip lenses 224 to 226 closeto the optical center of the pixel array unit 10 and the adjacenton-chip lenses 220, 221, and 229 close to the end portion of the pixelarray unit 10 are formed to have different sizes. For example, theadjacent on-chip lenses 224 to 226 are formed to have sizes smaller thanthe adjacent on-chip lenses 220, 221, and 229 arranged symmetricallywith respect to the common on-chip lens 320. Specifically, the adjacenton-chip lens 224 is formed to have a size smaller than the adjacenton-chip lens 229. Similarly, the adjacent on-chip lens 225 is formed tohave a size smaller than the adjacent on-chip lens 220, and the adjacenton-chip lens 226 is formed to have a size smaller than the adjacenton-chip lens 221.

Note that the common on-chip lens 320 is an example of a peripheralcommon on-chip lens described in the claims. Each of the adjacenton-chip lenses 220 to 229 is an example of a peripheral adjacent on-chiplens described in the claims. Note that each of the on-chip lenses 112is an example of the individual on-chip lens described in the claims.

Furthermore, the adjacent on-chip lens 225 arranged between the commonon-chip lens 320 and the optical center of the pixel array unit 10 isformed to have a size smaller than the adjacent on-chip lens 220arranged symmetrically with respect to the common on-chip lens 320.Furthermore, the adjacent on-chip lens 225 is formed to have a sizesmaller than an on-chip lens 112 adjacent to the adjacent on-chip lens225. Furthermore, the adjacent on-chip lens 220 is formed to have a sizelarger than an on-chip lens 112 adjacent to the adjacent on-chip lens220. Note that the adjacent on-chip lens 225 is an example of aperipheral close-adjacent on-chip lens described in the claims. Theadjacent on-chip lens 220 is an example of a peripheral far-adjacenton-chip lens described in the claims.

As described above, among the adjacent on-chip lenses 220 to 229, theadjacent on-chip lens arranged near the optical center of the pixelarray unit 10 is formed to have a size smaller than the adjacent on-chiplens arranged near the end portion of the pixel array unit 10. Inparticular, the adjacent on-chip lens 225 arranged between the commonon-chip lens 320 and the optical center of the pixel array unit 10 isformed to have the smallest size, and is formed to have a size smallerthan the on-chip lens 112 adjacent to the adjacent on-chip lens 225 andthe adjacent on-chip lens 220 arranged in an opposite position. Asdescribed above, the adjacent on-chip lenses 220 to 229 are adjusted tohave asymmetrical shapes. This adjustment is performed to level thesensitivity of the adjacent on-chip lenses 220 to 229 to the incidentlight components.

As described above, the adjacent on-chip lenses 220 to 229 are arrangedso as to be shifted in the direction of the optical center of the pixelarray unit 10 for the pupil correction. At this time, if the adjacenton-chip lenses 220 to 229 have shapes similar to the adjacent on-chiplenses 210 to 219 described with reference to FIG. 2 , the adjacenton-chip lens arranged near the optical center of the pixel array unit 10and the adjacent on-chip lens arranged near the end portion of the pixelarray unit 10 have different sensitivity characteristics. For example,the adjacent on-chip lens 225 without the above-described adjustment hashigher sensitivity than the adjacent on-chip lens 220 without theadjustment either. This is because the adjacent on-chip lenses areformed so as to overhang regions of the phase difference pixels 300, andthus, an effect of the pupil correction differs depending on a positionrelative to the common on-chip lens 320. Furthermore, as described withreference to FIG. 3 , the adjacent on-chip lenses have different depthsbetween end portions adjacent to the common on-chip lens 320 and endportions adjacent to the on-chip lenses 112, which causes the effect ofthe pupil correction to differ.

Therefore, the sensitivity can be leveled by the adjustment of the shapeas in the adjacent on-chip lenses 220 to 229 described above. Note that,in the vicinity of a right end of the pixel array unit 10, on-chiplenses and the like having shapes in which the on-chip lenses 112 andthe like in FIG. 12 are laterally inverted can be used. If the shapesand the positions of the resists 403 and 404 described with reference toFIG. 9 are changed, the common on-chip lens 320 and the adjacent on-chiplenses 220 to 229 can be formed.

FIG. 13 is a cross-sectional view illustrating a configuration exampleof the imaging element according to the second embodiment of the presentdisclosure. FIG. 13 is a cross-sectional view illustrating aconfiguration of a cross section of the imaging element 1 along a lineC-C′ in FIG. 12 . As illustrated in FIG. 13 , the adjacent on-chiplenses 220 and 225 are formed to have different shapes.

[Configuration of On-Chip Lens in Vicinity of Upper End of Pixel ArrayUnit] FIG. 14 is a diagram illustrating a configuration example of theon-chip lenses according to the second embodiment of the presentdisclosure. FIG. 14 illustrates a configuration example of on-chiplenses of pixels 100 and the like arranged in the vicinity of an upperend side, among the pixels 100 and the like arranged on the periphery ofthe pixel array unit 10 described with reference to FIG. 1 . The pixelarray unit 10 in FIG. 14 is different from the pixel array unit 10described with reference to FIG. 2 in the following points. The pixels100 in FIG. 14 include on-chip lenses 113 instead of the on-chip lenses110. The phase difference pixel adjacent pixels 200 in FIG. 14 includeadjacent on-chip lenses 230 to 239 instead of the adjacent on-chiplenses 210 to 219. The phase difference pixels 300 in FIG. 14 include acommon on-chip lens 330 instead of the common on-chip lens 310.

The on-chip lenses 113, the adjacent on-chip lenses 230 to 239, and thecommon on-chip lens 330 in FIG. 14 are arranged so as to be shifted to adownward direction, which is the direction of the optical center of thepixel array unit 10. Furthermore, among the adjacent on-chip lenses 230to 239, the adjacent on-chip lenses 236 to 239 close to the opticalcenter of the pixel array unit 10 and the adjacent on-chip lenses 231 to234 close to the end portion of the pixel array unit 10 are formed tohave different sizes. For example, the adjacent on-chip lenses 236 to239 are formed to have sizes smaller than the adjacent on-chip lenses231 to 234 arranged symmetrically with respect to the common on-chiplens 330. Specifically, the adjacent on-chip lenses 236 and 239 areformed to have sizes smaller than the adjacent on-chip lenses 231 and234, respectively. Similarly, the adjacent on-chip lenses 237 and 238are formed to have sizes smaller than the adjacent on-chip lenses 232and 233, respectively.

Note that the common on-chip lens 330 is an example of the peripheralcommon on-chip lens described in the claims. Each of the adjacenton-chip lenses 230 to 239 is an example of the peripheral adjacenton-chip lens described in the claims. Note that each of the on-chiplenses 113 is an example of the individual on-chip lens described in theclaims.

Furthermore, the adjacent on-chip lenses 237 and 238 arranged betweenthe common on-chip lens 330 and the optical center of the pixel arrayunit 10 are formed to have sizes smaller than the adjacent on-chiplenses 232 and 233 each arranged symmetrically with respect to thecommon on-chip lens 330. Furthermore, the adjacent on-chip lenses 237and 238 are formed to have sizes smaller than on-chip lenses 113adjacent to the adjacent on-chip lenses 237 and 238. In addition, theadjacent on-chip lenses 232 and 233 are formed to have sizes larger thanon-chip lenses 113 adjacent to the adjacent on-chip lenses 232 and 233.Note that each of the adjacent on-chip lenses 237 and 238 is an exampleof the peripheral close-adjacent on-chip lens described in the claims.Each of the adjacent on-chip lenses 232 and 233 is an example of theperipheral far-adjacent on-chip lens described in the claims.

As described above, among the adjacent on-chip lenses 230 to 239, theadjacent on-chip lens arranged near the optical center of the pixelarray unit 10 is formed to have a size smaller than the adjacent on-chiplens arranged near the end portion of the pixel array unit 10. Theadjacent on-chip lenses 237 and 238 arranged between the common on-chiplens 330 and the optical center of the pixel array unit 10 are formed tohave the smallest sizes, and are formed to have sizes smaller than theon-chip lenses 113 adjacent to the adjacent on-chip lenses 237 and 238and the adjacent on-chip lenses 232 and 233 in opposite positions.Similarly to the adjacent on-chip lenses 220 to 229 described withreference to FIG. 12 , the adjacent on-chip lenses 230 to 239 are formedto have asymmetrical shapes, so that the sensitivity of the adjacenton-chip lenses 230 to 239 to the incident light components can beleveled. Note that, in the vicinity of a lower end of the pixel arrayunit 10, on-chip lenses and the like having shapes in which the on-chiplenses 113 and the like in FIG. 14 are inverted upside down can be used.

FIG. 15 is a cross-sectional view illustrating a configuration exampleof the imaging element according to the second embodiment of the presentdisclosure. FIG. 15 is a cross-sectional view illustrating aconfiguration of a cross section of the imaging element 1 along a lineD-D′ in FIG. 14 . As illustrated in FIG. 15 , the adjacent on-chiplenses 233 and 237 are formed to have different shapes.

[Configuration of On-Chip Lens in Vicinity of Upper Left Corner of PixelArray Unit]

FIG. 16 is a diagram illustrating a configuration example of the on-chiplenses according to the second embodiment of the present disclosure.FIG. 16 illustrates a configuration example of on-chip lenses of pixels100 and the like arranged in the vicinity of an upper left corner, amongthe pixels 100 and the like arranged on the periphery of the pixel arrayunit 10 described with reference to FIG. 1 . The pixel array unit 10 inFIG. 16 is different from the piel array unit 10 described withreference to FIG. 2 in the following points. The pixels 100 in FIG. 16include on-chip lenses 114 instead of the on-chip lenses 110. The phasedifference pixel adjacent pixels 200 in FIG. 16 include adjacent on-chiplenses 240 to 249 instead of the adjacent on-chip lenses 210 to 219. Thephase difference pixels 300 in FIG. 16 include a common on-chip lens 340instead of the common on-chip lens 310.

The on-chip lenses 114, the adjacent on-chip lenses 240 to 249, and thecommon on-chip lens 340 in FIG. 16 are arranged so as to be shifted to alower right direction, which is the direction of the optical center ofthe pixel array unit 10. Furthermore, among the adjacent on-chip lenses240 to 249, the adjacent on-chip lenses 245 to 247 close to the opticalcenter of the pixel array unit 10 and the adjacent on-chip lenses 240 to242 close to the end portion of the pixel array unit 10 are formed tohave different sizes. For example, the adjacent on-chip lenses 245 to247 are formed to have sizes smaller than the adjacent on-chip lenses240 to 242 arranged symmetrically with respect to the common on-chiplens 340. Specifically, the adjacent on-chip lens 245 is formed to havea size smaller than the adjacent on-chip lens 240. Similarly, theadjacent on-chip lens 246 is formed to have a size smaller than theadjacent on-chip lens 241. The adjacent on-chip lens 247 is formed tohave a size smaller than the adjacent on-chip lens 242.

Note that the common on-chip lens 340 is an example of the peripheralcommon on-chip lens described in the claims. Each of the adjacenton-chip lenses 240 to 249 is an example of the peripheral adjacenton-chip lens described in the claims. Note that each of the on-chiplenses 114 is an example of the individual on-chip lens described in theclaims.

Furthermore, the adjacent on-chip lens 246 arranged between the commonon-chip lens 340 and the optical center of the pixel array unit 10 isformed to have a size smaller than the adjacent on-chip lens 241arranged symmetrically with respect to the common on-chip lens 340.Furthermore, the adjacent on-chip lens 246 is formed to have a sizesmaller than an on-chip lens 114 adjacent to the adjacent on-chip lens246. Furthermore, the adjacent on-chip lens 241 is formed to have a sizelarger than an on-chip lens 114 adjacent to the adjacent on-chip lens241. Note that the adjacent on-chip lens 246 is an example of theperipheral close-adjacent on-chip lens described in the claims. Theadjacent on-chip lens 241 is an example of the peripheral far-adjacenton-chip lens described in the claims.

As described above, among the adjacent on-chip lenses 240 to 249, theadjacent on-chip lens arranged near the optical center of the pixelarray unit 10 is formed to have a size smaller than the adjacent on-chiplens arranged near the end portion of the pixel array unit 10. Theadjacent on-chip lens 246 arranged between the common on-chip lens 340and the optical center of the pixel array unit 10 is formed to have thesmallest size, and is formed to have a size smaller than the on-chiplens 114 adjacent to the adjacent on-chip lens 246 and the adjacenton-chip lens 241 in an opposite position. Similarly to the adjacenton-chip lenses 220 to 229 described with reference to FIG. 12 , theadjacent on-chip lenses 240 to 249 are formed to have asymmetricalshapes, so that the sensitivity to the incident light components can beleveled. Note that, in a corner portion of the pixel array unit 10 otherthan the vicinity of the upper left corner, on-chip lenses and the likehaving shapes in which the on-chip lenses 114 and the like in FIG. 16are symmetrically inverted can be used.

Since other configurations of the imaging element 1 are similar to theconfigurations of the imaging element 1 described in the firstembodiment of the present disclosure, the description thereof will beomitted.

As described above, in the imaging element 1 of the second embodiment ofthe present disclosure, in a case where the pupil correction isperformed, the shapes of the common on-chip lens and the adjacenton-chip lenses are adjusted, so that the sensitivity of the adjacenton-chip lenses can be leveled. As a result, deterioration of imagequality can be prevented.

3. Third Embodiment

In the imaging element 1 of the above-described first embodiment, theadjacent on-chip lenses 210 to 219 are formed to have sizes larger thanthe on-chip lenses 110. On the other hand, an imaging element 1 of athird embodiment of the present disclosure is different from theabove-described first embodiment in that a part of the adjacent on-chiplenses 210 to 219 is formed to have a size larger than the on-chiplenses 110.

[Configuration of On-Chip Lens]

FIG. 17 is a diagram illustrating a configuration example of on-chiplenses according to the third embodiment of the present disclosure. Apixel array unit 10 in FIG. 17 is different from the pixel array unit 10described with reference to FIG. 2 in the following points. Phasedifference pixel adjacent pixels 200 in FIG. 17 include adjacent on-chiplenses 250 to 259 instead of the adjacent on-chip lenses 210 to 219.Phase difference pixels 300 in FIG. 17 include a common on-chip lens 350instead of the common on-chip lens 310.

Similarly to the adjacent on-chip lenses 210 to 219 described withreference to FIG. 2 , the adjacent on-chip lenses 250 to 259 in FIG. 17are formed to have sizes different from the on-chip lenses 110.Meanwhile, the common on-chip lens 350 is formed as a hexagon in whichsides corresponding to long sides of a rectangular shape formed with thetwo phase difference pixels 300 are shortened, and sides correspondingto short sides of the rectangular shape are lengthened, as compared withthe common on-chip lens 310 described with reference to FIG. 2 .Therefore, in the common on-chip lens 350, a shape of a bottom surfacecan be formed as a shape close to a circle, and the separation accuracyof pupil division can be improved. Such a shape of the common on-chiplens 350 can be formed if the adjacent on-chip lenses 252, 253, 257, and258 are formed to have sizes smaller than the on-chip lenses 110.

Since the adjacent on-chip lenses 250, 251, 254 to 256, and 259 areformed to have sizes larger than the on-chip lenses 110, similarly tothe adjacent on-chip lens 210 and the like in FIG. 2 , the adjacenton-chip lenses 250, 251, 254 to 256, and 259 are formed so as tooverhang regions of the phase difference pixels 300. On the other hand,since the adjacent on-chip lenses 252, 253, 257, and 258 are formed tohave smaller sizes, the common on-chip lens 350 is formed so as tooverhang regions of the phase difference pixel adjacent pixels 200corresponding to these adjacent on-chip lenses. Therefore, the shape ofthe bottom surface of the common on-chip lens 350 can be approximated toa circular shape.

[Configuration of Imaging Element]

FIGS. 18A, 18B, and 18C are cross-sectional views illustrating aconfiguration example of the imaging element according to the thirdembodiment of the present disclosure. FIG. 18A is a cross-sectional viewillustrating a configuration of a cross section of the imaging element 1along a line E-E′ in FIG. 17 . In FIG. 18A, the adjacent on-chip lenses250 and 255 are formed to have sizes larger than the on-chip lenses 110.Furthermore, FIG. 18B is a cross-sectional view illustrating aconfiguration of a cross section of the imaging element along a lineF-F′ in FIG. 17 . In FIG. 18B, the adjacent on-chip lenses 252 and 257are formed to have sizes smaller than the on-chip lenses 110.

Furthermore, FIG. 18C is a cross-sectional view illustrating aconfiguration of a cross section of the imaging element along a lineG-G′ in FIG. 17 , and illustrates a configuration of a cross section ofthe common on-chip lens 350 in an oblique direction. As described above,since the adjacent on-chip lenses 252 and 257 are formed to have sizessmaller than the on-chip lenses 110, the common on-chip lens 350overhangs the regions of the phase difference pixel adjacent pixels 200.As illustrated in FIG. 18C, the common on-chip lens 350 and the adjacenton-chip lenses 251 and 256 are formed to have shapes in which endportions of the common on-chip lens 350 and the adjacent on-chip lenses251 and 256 do not come into contact with each other. By adjusting theshapes of the adjacent on-chip lenses 250 to 259 in this way, it ispossible to approximate the shape of the bottom surface of the commonon-chip lens 350 to a circular shape.

Since other configurations of the imaging element 1 are similar to theconfigurations of the imaging element 1 described in the firstembodiment of the present disclosure, the description thereof will beomitted.

As described above, in the imaging element 1 of the third embodiment ofthe present disclosure, a part of the adjacent on-chip lenses 250 to 259is formed to have sizes larger than the on-chip lenses 110, and theother adjacent on-chip lenses are formed to have sizes smaller than theon-chip lenses 110. As a result, the shape of the common on-chip lens350 is adjusted, so that the separation accuracy of the pupil-dividedphase difference pixels 300 can be improved, and the focus detectionaccuracy can be improved.

4. Application Example to Camera

The technology according to the present disclosure (the presenttechnology) can be applied to various products. For example, the presenttechnology may be implemented as an imaging element mounted in animaging device such as a camera.

FIG. 19 is a block diagram illustrating a schematic configurationexample of a camera that is an example of an imaging device to which thepresent technology can be applied. A camera 1000 in FIG. 19 includes alens 1001, an imaging element 1002, an imaging control unit 1003, a lensdriving unit 1004, an image processing unit 1005, an operation inputunit 1006, a frame memory 1007, a display unit 1008, and a recordingunit 1009.

The lens 1001 is an imaging lens of the camera 1000. The lens 1001condenses light components from a subject and makes the light componentsincident on the imaging element 1002 described later to form an image ofthe subject.

The imaging element 1002 is a semiconductor element that images thelight components from the subject, which are condensed by the lens 1001.The imaging element 1002 generates an analog image signal according toan applied light component, converts the analog image signal into adigital image signal, and outputs the digital image signal.

The imaging control unit 1003 controls imaging by the imaging element1002. The imaging control unit 1003 generates a control signal andoutputs the control signal to the imaging element 1002 to control theimaging element 1002. Furthermore, the imaging control unit 1003 canperform autofocus in the camera 1000 on the basis of the image signaloutput from the imaging element 1002. Here, the autofocus is a systemthat detects a focal position of the lens 1001 and automatically adjustsa position of the lens 1001. As this autofocus, a method can be used inwhich an image plane phase difference is detected by phase differencepixels arranged in the imaging element 1002, so that the focal positionis detected (image plane phase difference autofocus). Furthermore, it isalso possible to apply a method of detecting, as the focal position, aposition where a contrast of an image is the highest (contrastautofocus). The imaging control unit 1003 adjusts the position of thelens 1001 via the lens driving unit 1004 on the basis of the detectedfocal position, to perform the autofocus. Note that the imaging controlunit 1003 can be configured by, for example, a digital signal processor(DSP) equipped with firmware.

The lens driving unit 1004 drives the lens 1001 under the control of theimaging control unit 1003. The lens driving unit 1004 can drive the lens1001 by changing the position of the lens 1001 using a built-in motor.

The image processing unit 1005 processes the image signal generated bythe imaging element 1002. This processing corresponds to, for example,demosaicing for generating image signals of insufficient colors amongimage signals corresponding to red, green, and blue for each pixel,noise reduction for removing noise of the image signals, encoding of theimage signals, and the like. The image processing unit 1005 can beconfigured by, for example, a microcomputer equipped with firmware.

The operation input unit 1006 receives an operation input from a user ofthe camera 1000. For the operation input unit 1006, for example, a pushbutton or a touch panel can be used. The operation input received by theoperation input unit 1006 is transmitted to the imaging control unit1003 and the image processing unit 1005. After that, processingaccording to the operation input such as processing of imaging thesubject is started, for example.

The frame memory 1007 is a memory that stores a frame that is imagesignals for one screen. The frame memory 1007 is controlled by the imageprocessing unit 1005 and holds the frame in a process of imageprocessing.

The display unit 1008 displays an image processed by the imageprocessing unit 1005. For the display unit 1008, a liquid crystal panelcan be used, for example.

The recording unit 1009 records the image processed by the imageprocessing unit 1005. For the recording unit 1009, a memory card or ahard disk can be used, for example.

The camera to which the present invention can be applied has beendescribed above. The present technology can be applied to the imagingelement 1002 among the configurations described above. Specifically, theimaging element 1 described with reference to FIG. 1 can be applied tothe imaging element 1002. By applying the imaging element 1 to theimaging element 1002, it is possible to perform autofocus using thephase difference pixels 300 of the imaging element 1.

Note that, although the camera has been described as an example here,the technology according to the present invention may be applied toanother device, for example, a monitoring device or the like.

Finally, the description of each of the above-described embodiments isan example of the present disclosure, and the present disclosure is notlimited to the above-described embodiments. Therefore, it is needless tosay that, besides each of the above-described embodiments, variouschanges can be made according to the design or the like as long as thechanges do not depart from the technical concept according to thepresent disclosure.

Note that the present technology may have the following configurations.

-   (1) An imaging element including    -   a pixel array unit in which pixels that perform photoelectric        conversion according to incident light components, a plurality        of phase difference pixels that is included in the pixels, is        arranged adjacent to each other, and detects a phase difference,        and phase difference pixel adjacent pixels that are included in        the pixels and are adjacent to the phase difference pixels are        arranged two-dimensionally,    -   an individual on-chip lens that is arranged for each of the        pixels and individually condenses the incident light components        on corresponding one of the pixels,    -   a common on-chip lens that is commonly arranged in the plurality        of phase difference pixels and commonly condenses the incident        light components, and    -   an adjacent on-chip lens that is arranged for each of the phase        difference pixel adjacent pixels, individually condenses the        incident light components on corresponding one of the phase        difference pixel adjacent pixels, and is formed to have a size        different from the individual on-chip lens to adjust a shape of        the common on-chip lens.-   (2) The imaging element according to (1), in which the adjacent    on-chip lens is formed to have a size larger than the individual    on-chip lens.-   (3) The imaging element according to (2), in which the adjacent    on-chip lens is formed to have a bottom portion with a width larger    than the individual on-chip lens.-   (4) The imaging element according to (2), in which an adjacent    on-chip lens adjacent to the common on-chip lens at an apex is    formed to have a size larger than an adjacent on-chip lens adjacent    to the common on-chip lens on a side.-   (5) The imaging element according to any of (1) to (4), in which    -   the individual on-chip lens is arranged so that a position        relative to corresponding one of the pixels is shifted according        to an incident angle of the incident light components,    -   the adjacent on-chip lens is arranged so that a position        relative to corresponding one of the phase difference pixel        adjacent pixels is shifted according to the incident angle of        the incident light components, and    -   the common on-chip lens is arranged so that a position relative        to the phase difference pixels is shifted according to the        incident angle of the incident light components.-   (6) The imaging element according to (5), in which, among peripheral    adjacent on-chip lenses that are adjacent on-chip lenses adjacent to    a peripheral common on-chip lens which is a common on-chip lens    arranged in a periphery of the pixel array unit, a peripheral    adjacent on-chip lens close to an optical center of the pixel array    unit and a peripheral adjacent on-chip lens close to an end portion    of the pixel array unit are formed to have different sizes.-   (7) The imaging element according to (6), in which, among the    peripheral adjacent on-chip lenses, the peripheral adjacent on-chip    lens close to the optical center of the pixel array unit is formed    to have a size smaller than the peripheral adjacent on-chip lens    close to the end portion of the pixel array unit, which is arranged    symmetrically with respect to the peripheral common on-chip lens.-   (8) The imaging element according to (6), in which a peripheral    close-adjacent on-chip lens that is a peripheral adjacent on-chip    lens arranged between the peripheral common on-chip lens and the    optical center of the pixel array unit is formed to have a size    smaller than a peripheral far-adjacent on-chip lens that is a    peripheral adjacent on-chip lens arranged symmetrically with respect    to the peripheral common on-chip lens.-   (9) The imaging element according to (8), in which the peripheral    close-adjacent on-chip lens is formed to have a size smaller than an    individual on-chip lens adjacent to the peripheral close-adjacent    on-chip lens.-   (10) The imaging element according to (8), in which the peripheral    far-adjacent on-chip lens is formed to have a size larger than an    individual on-chip lens adjacent to the peripheral far-adjacent    on-chip lens.-   (11) The imaging element according to any of (1) to (10), in which    the adjacent on-chip lens is formed at different heights between a    bottom portion of a region adjacent to the common on-chip lens and a    bottom portion of a region adjacent to the individual on-chip lens.-   (12) The imaging element according to any of (1) to (11), in which a    shape of a bottom surface of the adjacent on-chip lens is formed as    a shape different from a bottom surface of the phase difference    pixel adjacent pixels.-   (13) The imaging element according to any of (1) to (12), in which    the common on-chip lens commonly condenses the incident light    components on two of the phase difference pixels.-   (14) The imaging element according to any of (1) to (12), in which    the common on-chip lens commonly condenses the incident light    components on four of the phase difference pixels.-   (15) The imaging element according to any of (1) to (14), in which    the plurality of phase difference pixels performs pupil division on    the incident light components to detect the phase difference.-   (16) A method for manufacturing an imaging element, the method    including a step of forming a pixel array unit in which pixels that    perform photoelectric conversion according to incident light    components, a plurality of phase difference pixels that is included    in the pixels, is arranged adjacent to each other, and detects a    phase difference, and phase difference pixel adjacent pixels that    are included in the pixels and are adjacent to the phase difference    pixels are arranged two-dimensionally,    -   a step of forming an individual on-chip lens that is arranged        for each of the pixels and individually condenses the incident        light components on corresponding one of the pixels,    -   a step of forming a common on-chip lens that is commonly        arranged in the plurality of phase difference pixels and        commonly condenses the incident light components, and    -   a step of forming an adjacent on-chip lens that is arranged for        each of the phase difference pixel adjacent pixels, individually        condenses the incident light components on corresponding one of        the phase difference pixel adjacent pixels, and is formed to        have a size different from the individual on-chip lens to adjust        a shape of the common on-chip lens.

Reference Signs List 1 Imaging Element 10 Pixel Array Unit 100 Pixel101, 301 End Portion 110, 112, 114 On-Chip Lens 141 Color Filter 142Light-Shield Film 152 Seperation Portion 154 Seperation Region 155, 406,407 Gap 200 Phase Difference Pixel Adjacent Pixel 210 to 219 AdjacentOn-Chip Lens 220 to 239 Adjacent On-Chip Lens 230 to 239 AdjacentOn-Chip Lens 240 to 249 Adjacent On-Chip Lens 250 to 259 AdjacentOn-Chip Lens 300 Phase Difference Pixel 310, 320, 330, 340, 350 CommonOn-Chip Lens 403 to 405 Resist 1002 Imaging Element 1005 ImageProcessing Unit

1] A light detecting device comprising: a first pixel comprising: afirst photoelectric conversion region; and a first on-chip lensconfigured to individually condense incident light on the firstphotoelectric conversion region; a plurality of second pixelscomprising: a plurality of second photoelectric conversion regions; anda second on-chip lens configured to commonly condense incident light onthe plurality of second photoelectric conversion regions; and a thirdpixel disposed between the first pixel and the plurality of secondpixels, the third pixel comprising: a third photoelectric conversionregion; and a third on-chip lens configured to individually condenseincident light on the third photoelectric conversion region, wherein, ina cross-sectional view, a surface of the third on-chip lens comprises afirst edge and a second edge opposite to the first edge, the first edgeis disposed adjacent to the first on-chip lens and the second edge isdisposed adjacent to the second on-chip lens, and the first edge isdifferent in a height from the second edge. 2] The light detectingdevice according to claim 1, wherein the third pixel is disposedadjacent to the first pixel and disposed adjacent to the plurality ofsecond pixels. 3] The light detecting device according to claim 1,wherein the first edge is larger in a height than the second edge. 4]The light detecting device according to claim 1, wherein, in a planview, the third on-chip lens is different in a shape from the firston-chip lens. 5] The light detecting device according to claim 1,wherein, in a plan view, the third on-chip lens is different in a shapefrom the second on-chip lens. 6] The light detecting device according toclaim 1, wherein, in a plan view, the third on-chip lens is different ina shape from the first on-chip lens and the second on-chip lens. 7] Thelight detecting device according to claim 1, wherein, in a plan view,the third on-chip lens is lager in a size than the first on-chip lens.8] The light detecting device according to claim 1, wherein, in a planview, the third on-chip lens is smaller in a size than the secondon-chip lens. 9] The light detecting device according to claim 1,wherein, in a plan view, the third on-chip lens is lager in a size thanthe first on-chip lens and smaller in a size than the second on-chiplens. 10] The light detecting device according to claim 1, wherein, in aplan view, the third on-chip lens is different in a shape from the thirdpixel. 11] The light detecting device according to claim 1, wherein theplurality of second pixels are pixels for detecting an image plane phasedifference. 12] The light detecting device according to claim 1, whereinthe second on-chip lens is configured to commonly condense incidentlight on two of the second photoelectric conversion regions. 13] Thelight detecting device according to claim 1, wherein the second on-chiplens is configured to commonly condense incident light on four of thesecond photoelectric conversion regions. 14] A camera comprising: alens; an image processing unit; and a light detecting device comprising:a first pixel comprising: a first photoelectric conversion region; and afirst on-chip lens configured to individually condense incident light onthe first photoelectric conversion region; a plurality of second pixelscomprising: a plurality of second photoelectric conversion regions; anda second on-chip lens configured to commonly condense incident light onthe plurality of second photoelectric conversion regions; and a thirdpixel disposed between the first pixel and the plurality of secondpixels, the third pixel comprising: a third photoelectric conversionregion; and a third on-chip lens configured to individually condenseincident light on the third photoelectric conversion region, wherein, ina cross-sectional view, a surface of the third on-chip lens comprises afirst edge and a second edge opposite to the first edge, the first edgeis disposed adjacent to the first on-chip lens and the second edge isdisposed adjacent to the second on-chip lens, and the first edge isdifferent in a height from the second edge.